OUR STUDY OF THE ROLE OF THE PRIMARY INFECTION IN THE SPREAD OF THE HIV APPEARED IN THE J. AIDS IN NOVEMBER, 1994. THAT PAPER HAS HAD A MAJOR IMPACT ON THE FIELD. NOW, MOST WORKERS IN THE FIELD ARE CONVINCED THAT THE PRIMARY INFECTION IS THE MOST INFECTIOUS PERIOD OF THE DISEASE. OUR SUBSEQUENT WORK HAS SHOWN THAT EVEN IN THE ENDEMIC STATE, A MAJOR PORTION OF THE TRANSMISSIONS COME FROM INDIVIDUALS WHO ARE IN THE PRIMARY INFECTION. THAT HAS LED US TO INVESTIGATE THE POTENTIAL OF VACCINES FOR CONTROL OF THE SPREAD OF THE HIV. OUR CURRENT RESULTS STRONGLY SUGGEST THAT A VACCINE THAT DOES NOT PREVENT INFECTION (HIGHLY LIKELY WITH THE HIV) BUT THAT CAN MARKEDLY DECREASE THE VIREMIA OF THE PRIMARY INFECTION COULD DECREASE SPREAD SUFFICIENTLY TO STOP THE EPIDEMIC.